xen_mm_pin_all()/unpin_all() are used to implement full guest instance
suspend/restore. It's a stop-all method that needs to iterate through
all allocated pgds in the system to fix them up for Xen's use.
This code uses pgd_list, probably because it was an easy interface.
But we want to remove the pgd_list, so convert the code over to walk
all tasks in the system. This is an equivalent method.
(As I don't use Xen this is was only build tested.)
Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Waiman Long <Waiman.Long@xxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/xen/mmu.c | 45 +++++++++++++++++++++++++++++++++++++++------
1 file changed, 39 insertions(+), 6 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 9c479fe40459..96bb4a7a626d 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -45,6 +45,7 @@
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/gfp.h>
+#include <linux/oom.h>
#include <linux/memblock.h>
#include <linux/seq_file.h>
#include <linux/crash_dump.h>
@@ -854,18 +855,34 @@ static void xen_pgd_pin(struct mm_struct *mm)
*/
void xen_mm_pin_all(void)
{
- struct page *page;
+ struct task_struct *g;
+ rcu_read_lock(); /* Task list walk */
spin_lock(&pgd_lock);
- list_for_each_entry(page, &pgd_list, lru) {
+ for_each_process(g) {
+ struct task_struct *p;
+ struct mm_struct *mm;
+ struct page *page;
+ pgd_t *pgd;
+
+ p = find_lock_task_mm(g);
+ if (!p)
+ continue;
+
+ mm = p->mm;
+ pgd = mm->pgd;
+ page = virt_to_page(pgd);
+
if (!PagePinned(page)) {
- __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
+ __xen_pgd_pin(&init_mm, pgd);
SetPageSavePinned(page);
}
+ task_unlock(p);
}
spin_unlock(&pgd_lock);
+ rcu_read_unlock();
}
/*
@@ -968,19 +985,35 @@ static void xen_pgd_unpin(struct mm_struct *mm)
*/
void xen_mm_unpin_all(void)
{
- struct page *page;
+ struct task_struct *g;
+ rcu_read_lock(); /* Task list walk */
spin_lock(&pgd_lock);
- list_for_each_entry(page, &pgd_list, lru) {
+ for_each_process(g) {
+ struct task_struct *p;
+ struct mm_struct *mm;
+ struct page *page;
+ pgd_t *pgd;
+
+ p = find_lock_task_mm(g);
+ if (!p)
+ continue;
+
+ mm = p->mm;
+ pgd = mm->pgd;
+ page = virt_to_page(pgd);
+
if (PageSavePinned(page)) {
BUG_ON(!PagePinned(page));
- __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
+ __xen_pgd_unpin(&init_mm, pgd);
ClearPageSavePinned(page);
}
+ task_unlock(p);
}
spin_unlock(&pgd_lock);
+ rcu_read_unlock();
}
static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
--
2.1.4
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